1. Field of the Invention
The present invention generally relates to an information recording and reproducing apparatus in which power is controlled when information is being recorded in an information recording medium.
2. Description of the Related Art
As a recording medium capable of recording a large amount of information, there are a CD-R and a CD-RW. Recently, as a recording medium capable of recording a much larger amount of information, a DVD+R and a DVD+RW have been replacing the CD-R and the CD-RW in the market place. When information is recorded in these media, a driver performs an operation called OPC (optimum power control & calibration). In the OPC operation, test writing is performed in a test writing zone by changing laser power in several steps; then, optimum power is determined. This test writing zone is called a PCA (power calibration area) in the CD-R and the CD-RW, inner and outer disc test zones in the DVD+R, and inner and outer drive test zones in the DVD+RW.
In addition to the OPC operation, as a typical power control method, there is an ROPC (running OPC) operation. In the ROPC operation, the disc status during recording of information is always monitored and recording is performed by controlling power. Recently, recording speeds have become high and 16 times standard recording speed can be performed in the DVD+R and the DVD+RW.
As a conventional technology, Patent Document 1 aims to form an excellent recording mark, even if optimum recording power is changed by differences of recording sensitivity among discs or difference of ambient temperature. In order to achieve this, an information recording apparatus, which forms an information recording mark by irradiating an optical beam onto a disc, is disclosed. The information recording apparatus includes a test writing unit which performs test writing by changing recording power of an optical beam and a rotational speed deciding unit which determines the rotational speed at the time of recording information by using the test writing results.
[Patent Document 1] Japanese Laid-Open Patent Application No. 9-288827
However, in the case of the above high-speed recording, even if information is recorded under optimum conditions by the ROPC operation in the inner small radius region and the middle medium radius region of a disc, with those same conditions, the information cannot be recorded optimally in the outer large radius region and near the outer region. Consequently, in some cases, recording quality is degraded. These problems are caused by ambient temperature, bowing of the disc, mechanical characteristics of the apparatus, and so on. In this case, higher recording power is required than usual; therefore, the usual power is supplemented by the ROPC operation. However, in the case of the high 16-times recording speed, this supplement is not applied in time, so that the difference in the recording power cannot be compensated for. Consequently, recording quality is degraded and recorded data cannot be read.
In the technology described in Patent Document 1, test writing is performed before usual recording and the rotational speed is controlled according to the results of the test writing when the usual recording is performed. However, as described above, since it is not taken into consideration that the recording power is influenced by the bowing of the disc and the mechanical characteristics of the apparatus, the correction cannot be applied in time due to high-speed recording.